Non-crystalline heat-resistant resins such as polyphenylene ether resins, polycarbonate resins, polysulfone resins, polyethersulfone resins, polyarylate resins, polyamide-imide resins, polyetherimide resins and thermoplastic polyimide resins (most of these are also known as “super engineering plastics”) have a merit of having high heat resistance, but the fluidity when molding is insufficient. Fluidity can thus be conferred by adding plasticizers and flame retardants into the above heat-resistance resins, but there may be a problem that the heat resistance as a resin deteriorates. Thus, there is a demand for the heat-resistant resins to confer fluidity while still maintaining a high degree of heat resistance.
More specifically, polyphenylene ether resins have excellent properties such as heat resistance, water-absorbing property, dimensional stability, and mechanical and electrical properties, and are used, for example, in various applications such as industrial goods, electrical/electronic components, office equipment, various housings, automobile parts, and precision parts. However, with a polyphenylene ether resin alone, there is a lack of fluidity, chemical resistance and so on, and hence alloying with another resin such as polystyrene is widely known. However, if high impact polystyrene or the like is added into the polyphenylene ether resins, then the resin generally loses transparency. Polyphenylene ether resin compositions that have good fluidity conferred thereon while maintaining a high degree of heat resistance, and are transparent, although colored, have thus been desired. In addition, resin compositions containing a high polyphenylene ether proportion therein have a very high melt viscosity, and hence the processing temperature must be made to be approximately 300° C., whereupon degradation, gelation and so on becomes prone to occur, thereby causing foreign matter to arise in products. Such foreign matter causes a deterioration in properties, a deterioration in the external appearance of products and so on, and hence there are strong needs in industry to reduce the amount of, or if possible eliminate, such foreign matter.
From the viewpoint of suppressing oxidative degradation and thermal degradation of a polymer, there has been proposed to add a high melting point hindered phenol into polyphenylene ether, but an amount of the phenolic additive is very low, i.e. not sufficient for the phenolic additive to act as a fluidity-conferring agent, and also insufficient with regard to transparency and metering stability (See, for example, Japanese Patent Application Laid-open No. 07-32454, Japanese Patent Application Laid-open No. 07-145308, Japanese Patent Application Laid-open No. 07-150000).
As a technology for conferring fluidity while maintaining heat resistance, on one hand, there has been proposed to alloy a polyphenylene ether with a liquid-crystal polyester (See, for example, Japanese Patent Application Laid-open No. 07-70394, Japanese Patent Application Laid-open No. 7-3137, Japanese Patent Application Laid-open No. 6-122762). However, there is no mention of liquid paraffin in these documents, nor is there any mention of reducing the amount of foreign matter, generation of fines, or bleeding out.
On the other hand, there has been proposed to add a white oil into a polyphenylene ether and a liquid-crystal polyester (See, for example, Japanese Patent Application Laid-open No. 05-202273, Japanese Patent Application Laid-open No. 05-239322), but in these documents the proportion of the liquid-crystal polyester is high, and hence the liquid-crystal polyester is the material forming a continuous phase, and moreover there is no mention of reducing the amount of foreign matter and generation of fines.
Further, there has been proposed to add an aromatic compound such as tertiary butyl hydroquinone as a compatibilizer for a polyphenylene ether a the liquid-crystal polyester (See, for example, Japanese Patent Application Laid-open No. 10-500448), but all such compatibilizer has a molecular weight of less than 400, and moreover there is no mention of reducing the amount of foreign matter, achieving both good heat resistance and good fluidity, or generation of fines.
Furthermore, there has been proposed to blend an antioxidant into an alloy of a polyphenylene ether and a liquid-crystal polyester, but only common antioxidants are mentioned in this document, and moreover there is no mention of reducing the amount of foreign matter, or generation of fines (See, for example, Japanese Patent Application Laid-open No. 02-97555).
Moreover, there has been proposed a blend of a polyphenylene ether, a liquid-crystal polyester, and a hydrocarbon wax, but there is no mention of a specific phenolic stabilizer, and there is also no mention of reducing the amount of foreign matter, or generation of fines (Japanese Patent Application Laid-open No. 2004-121).